I find something else to do...

Avoid them anyway I can

Leave them to it.

Stop listening. They can either try to be positive and make the best of a situation or continue to be unhappy. It's their choice, it's your choice whether you encourage the latter option

i live with one of those, you just offer them positivity and if they don't take it then you get on with your day.

You can try to cheer them up. Maybe there's a reason why they moan. Maybe they should broaden their horizons. Geographically and intellectually speaking.

i say there are people out there much worse off than you so shut the f ck up

Ignore and avoid them.

Probably not invite them to watch a good film with me😊